I tried winter sowing for the first time last year, with poor results, only three out of 20 tries sprouted. So this year I didn't expect much but at least I did better than last year. I used half-gallon milk jugs sliced halfway down 3/4 of the way around, so I could hinge them open to plant (and hopefully reap) the seeds. I punched holes in the bottom for drainage and cut some openings in the top to get precipitation and aeration, put in the seeds in Jan. or Feb., put them out on the deck and left them alone til March-April when I started looking for green. Here's what happened.
Name seedlings harvested / seeds planted
Lobelia cardinalis 8/ ~25 (too small to count)
Liatris 4/ 6-8
Aster perser 5/ 8
Baptisia australis 3/8
Salvia azorea 1/6
Salvia regeliana 1/6
Lobelia syphilitica 0/~25
Phlox paniculata 0/6
Well, I really wasn't expecting much from the Iris or Phlox, since planting them indoors gave poor yields too, but I was disappointed at the Salvia and the L. syphilitica, considering that the L. cardinalis did well.
So, I guess the results, though not outstanding, were good enough to try some more perennials next year, so I will peruse the posts on this forum carefully for hints as to what might do better.
I had amazing luck with different types of daisies, corn flowers, cone flowers, rudbeckia, sedum, coral bells, delphinium, dianthus, and lupine. The more exotic seeds I tried - nope - no good. I also put about 50 seeds/gallon jug to make sure I got some to germinate. Even if only 10 germinated, it's still cheaper than buying them at the nursery. On www.wintersown.org there is a list of which seeds are best to sow.
Mine went out in January and sat under three feet of snow for a month or two. Amazing results.
I had a rough wintersowing year, too. We had a longer than usual and colder than usual winter, so they got a slow start. Then the pill bugs went crazy and ate many of my babies. Unfortunately, I'm just now realizing what got 'em, so I wasn't able to get them under control in time to save so many. Last year, however, was absolutely wonderful, so I will definately try again. Next year, I will be prepared for those pill bugs!
I started all my tomato seeds in gallon milk jugs the weekends of January 9th and 16th. I also started 2 kinds of bell peppers by mistake (didn't realize they needed HEAT, so even though I WSed them in the jugs, they stayed inside under my fluorescent lights until plant out).
The tomatoes stayed outside until plantout in March. I potted them up to individual 16 oz. Red Solo cups and put them into one tall and one short Sterilite container. The Seedlings in the taller container were protected from the wind, and grew stouter and beefier than what was on sale at HD and Lowe's! Best seedlings I ever grew. The unprotected seedlings took longer to beef up, but eventually did.
Here's a pic of my seedlings, before they went into the Sterilite containers. I'm sold on WSing my spring veggie seeds from now on. No more inside grow lights for me (except for the bell peppers!)